1. Field of the Invention
The present invention pertains to automotive fasteners. More particularly, the present invention pertains to automotive fasteners having a parabolic shaped coating adhered to the tip of the fastener to prevent scratching during installations and the process of producing the same.
2. Prior Art
There exists the need for an automotive fastener that can be used to attach automotive components to a vehicle without damaging the decorative coating that has been applied to the body of the vehicle.
During the assembly process, fasteners of the general type disclosed in this invention are welded to a bracket, such as a bumper mounting bracket, to allow attachment of various components to a vehicle body. The mounting bracket assemblies are commonly treated to prevent corrosion by processing with caustic and acid washes, with a subsequent electrodeposited paint coating.
During installation of the bracket assembly, the tips of the fasteners have been known to damage the decorative coating of the vehicle body. The damage is predominantly caused when a person attempts to install the bracket assembly at an angle other than perpendicular to a mounting hole. When attempting to install the bracket assembly at an angle, the fastener tip may be dragged across the vehicle body thereby scratching the decorative coating.
It is an object of this invention to provide a fastener having a parabolic shaped coating applied to the tip of the fastener to prevent scratching of the decorative coating of a vehicle during installation. It is a further object of this invention to provide a fastener having a parabolic shaped coating applied to the tip of the fastener, where the coating can withstand the welding and corrosion treatment outlined above.
Various fasteners having coatings are known, U.S. Pat. No. 4,692,080 entitled xe2x80x9cSelf Drilling Fasteners And Process For Making The Samexe2x80x9d, discloses a self-drilling screw having a frangible polymer coating on the screw tip. The coating is applied prior to applying a corrosion resistant plating to the screw for preventing the plating from being deposited upon the tips of the fasteners. The coating comprises a triallyl cyanurate which is ultra-violet or infrared curable. The coating breaks away from the fastener during the installation process, to expose the sharp self-drilling tip of the disclosed fastener.
The fastener of the above referenced patent does not provide a fastener having a parabolic shaped coating on the tip that will not break off during the installation process, thereby preventing the scratching of the decorative coating of the vehicle body.
U.S. Pat. No. 4,713,855 entitled xe2x80x9cProcess For Making Self-Drilling Fastenersxe2x80x9d, discloses a process for manufacturing the fasteners outlined in the previously referenced U.S. Pat. No. 4,692,080. The patent discloses a process for applying the frangible coating to the self-tapping screw tip which includes dipping the tip into a triallyl cyanurate polymer bath and subsequently curing the polymer using ultra-violet or infrared light.
The process of the above referenced patent does not provide a process for applying a coating to the tip of a fastener, to produce a parabolic shaped coating on the tip.
It is therefore, the purpose of the present invention to cure those deficiencies outlined above by providing a fastener and the process for producing the same, whereby the tip of the fastener has a parabolic shaped coating adhered to the tip of the fastener to prevent scratching of the decorative coating of a vehicle during installation.
Thus, in accordance with the present invention, there is provided a process for making a fastener having a shank with a head and a flat tip. A polymeric coating is applied to the flat tip to form a parabolic bubble on the tip of the fastener. The bubble is cured to prevent the tip of the fastener from damaging a decorative coating on a vehicle, such as during installation of the fastener.
The invention includes the several steps and the relationship of the several steps with respect to each other. The invention also includes the article produced by the process and its properties as disclosed in the following Detailed Description.